struct2 实现文件下载时无法获取文件名

Question

1.action类

public String doDownLoad() throws InstantiationException, IllegalAccessException, IOException{
        String fid=request.getParameter("fid");//从页面获取文件id如果为空返回异常；
     if(fid==null){
        return Action.ERROR;
       }
        FileBean fileBean= new FileSevice().getFile(fid);//从数据库获取文件bean如果为空返回异常；
     System.out.println("fileBean:"+fileBean);
     if(fileBean==null){
        return Action.ERROR;    
       }
        String path = fileBean.getPath();//判断路径和文件名称是否为空，如果为空返回异常;
        System.out.println("FileName:"+fileBean.getFileName());
        this.fileFileName=new String(fileBean.getFileName().getBytes(),"ISO8859-1");
     if(path==null||this.fileFileName==null){
        return Action.ERROR;    
       }
        File files = new File(path);
     if(!files.exists()){
         return Action.ERROR;
        }
        this.fileFileContentType = fileFileName.substring(fileFileName.lastIndexOf("."));
        System.out.println("fileFileContentType:"+this.fileFileContentType);
        inputStream = new FileInputStream(files);
        this.fileFileName = fileBean.getFileName();
        contentLength = inputStream.available();
        return Action.SUCCESS;
      }
 }

2.struct2配置
<action name="downProjectFile" class="com.ipvr.edu.Action.ProjectFile" method="doDownLoad">

      <result type="stream">
          <param name="inputstream">inputStream</param>
          <param name="contentDisposition">attachment;fileName="${fileFileName}"</param>
          <param name="contentType">application/octet-stream</param>
          <param name="bufferSize">2048</param>
       </result>
       <result name="error">error.html</result>
   </action>

3.输出
fileBean:FileBean [fileId=73, fileName=总体设计文档.docx, type=file, path=C:apache-tomcat-7.0.70webappsTx4.0fileprojectFile20170515192926248.docx, upTime=2017-05-15 19:29:26.0, visble=1+contentnull]
FileName:总体设计文档.docx
fileFileContentType:.docx